The present invention relates to a device for severing mooring lines and cables under water and more particularly the present invention relates to a device which is used in conjunction with an apparatus for controlling the depth of a marine cable, such as a geophysical exploration cable during marine seismic explorations. During such explorations a boat drags a length of a cable to which a plurality of depth control units are secured. The depth control units which are constructed with a pair of planes or "wings" which are transversely located on an elongated body of the control unit, so as to insure the desired submersion depth of the exploration cable which is critical in obtaining true and correct recordings of seismic conditions in the explorated area. It has been a continuous problem for such explorations that a number of mooring lines from fishing nets or buoys are present in the area of exploration, with the mooring lines, cables and the like cutting into the body of the guiding planes, often times damaging them to a degree, wherein the length of the cable has to be pulled out of the water and the control unit be replaced before the operation is resumed.
In order to solve the problem, a number of solutions have been offered, some of them consisting of providing the depth control apparatus with a deflection means which are mounted forwardly from the guiding planes, so as to deflect any possible obstruction away from the guiding planes and prevent the damage thereof. Other solutions include mechanical mechanisms or a combination of explosive and mechanical mechanisms which are released or otherwise actuated by a trigger upon contact with the mooring line or cables to be cut. Such devices, however, require a substantive modification of the cable depth control apparatuses to prevent damage to the impact sensitive guiding planes.
The present invention contemplates provision of a simple and inexpensive device for severing underwater mooring lines, cables and the like which can be easily adapted for use with the cable depth control apparatus.